Mechanized equipment such as backhoes and tractors having lift arms can be used with various work implements such as buckets, blades, and lift forks. The implement is mounted on the lift arm to facilitate operation and use of the implement. Various mechanisms have been proposed to allow quick interchanging of these work implements so the same tractor can be used for different work functions. Generally, the implement and lift arm are modified or provided with attachment members to releasably mount the various implements on the lift arm to permit quick changing.
Some of these quick change mechanisms rely on pins which must be inserted into aligned holes in the implement and mounting brackets on the lift arm. Unfortunately, this type of mechanism can require careful and time consuming alignment of the holes. The pins often must be particularly robust to prevent misalignment problems and to carry the load of the implement. Additionally, the pins are exposed to dirt and tend to wear unevenly causing undesirable looseness and misalignment in the coupling.
Other mechanisms proposed have relatively large and complicated linkages. These mechanisms consist of a female member mounted on the implement and an expandable male member mounted on the lift arm of the tractor. The male member has a hinge-like structure which is expanded to engage the female member. Such mechanisms often use hydraulic cylinders.
Some of these mechanisms are particularly complex and can offset the balance of the tractor by placing an excessive weight on the end of the lift arm. In addition, the hydraulic system can leak causing the inadvertent disengagement of the implement from the tractor. Other devices have complicated locking mechanisms in a relatively inaccessible location making implement changing difficult for the operator.
Accordingly, it would be desirable to provide a coupler assembly which avoids the deficiencies of the prior art and is easy to use and provides sure coupling of an implement on a lift arm. The present invention meets that desire.